Roller presses are used for briquetting, pulverising and compacting processes in processing plants. Granulates are charged between two rollers via a feed chute. The rollers press the granulate together, pulverise it or compact it. Roller presses thus modify the granulate condition of the initial material and, for example, briquettes are formed or fine dusts produced. In doing this the rollers are subject to substantial wear and must be serviced or replaced at certain intervals. Such replacement and service work and also the related inspections involve downtimes of the roller press and of the associated complete processing plant.
With regard to the availability of a processing plant there is the task of minimizing the downtimes for roller presses, because during briquetting, pulverising and compacting the downtimes of the equipment are essentially determined by the replacement of worn tools, i.e. roller linings, segments, etc. For the tool replacement the rollers, on which the tools are located, must be removed from the machine. For processes in which a roller press is operated in a key position, high outage costs may then arise due to the downtimes during roller changes. Particularly during the operation of a number of machines in a process, for example during hot briquetting, service work accounts for a large amount of time.
Various opening mechanisms are known for carrying out servicing or roller changes on a roller press. In this respect both hinged frames are used which permit a fast change of roller and also frames which must be partially dismantled for a change of roller. When selecting a suitable machine frame for a roller press, various aspects must be considered, from the use of the roller press to the siting position.
With the selection of a hinged frame which permits the change of roller only on one side of the machine only a small area is needed for siting the equipment, because in this case only one side flap must be opened up. Here, apart from a head piece of the frame, this side flap may also include a part of the frame top wall which is permanently joined to the head piece and is used as an end stop when withdrawing the rollers. However, in order to be able to change or service the rear roller of the pair of rollers, with this sort of single-sided hinged frame the front roller must also in each case be removed, which is obstructive in the case of the exclusive change or inspection of the rear roller. However, an advantage is that with a single-sided hinged frame both rollers can be lifted by an overhead crane and be transported without the feed chute of the roller press having to be dismantled (refer to FIG. 4).
With a hinged frame which permits a change of rollers from both sides of the machine, a larger area is needed for the equipment, because both side regions, i.e. head pieces, of the frame must be opened up. This type of double-sided hinged frame facilitates the convenient removal of both rollers of the pair of rollers independently. Also the material feed walls and the tongues of the metering hopper do not need to be dismantled. However, for lifting the rollers an overhead crane is needed on both sides of the roller press, because the metering hopper and the bunker over the roller press prevent access of a single overhead crane to both sides of the hinged frame (refer to FIG. 5).
Roller frames, which cannot be swivelled out, but rather in which the upper region of the machine must be dismantled, exhibit significantly increased assembly effort compared to hinged frames. For changing the rollers the metering hopper unit must be taken down and removed via complicated moving mechanisms. Apart from the intensity of the work, the time required with such frames for changing or servicing the rollers is significantly increased compared to hinged frames.